Merge PDF files — free, no upload

Yes — 100% free, no signup, no watermark, no daily quota. Merge as many PDF files as you want, as often as you want. Smallpdf caps free users at 2 files per day before pushing the $9/month plan, iLovePDF Premium starts at $7/month, Adobe Acrobat Pro at $19.99/month, Sejda at $7.50/month with a 50 MB cap, PDF24 is free but uploads everything to German servers — iFillPDF is free and processes locally.

Directly in your browser, in your own RAM, via a WebAssembly engine — nothing is uploaded to our servers. This is the structural difference vs iLovePDF, Smallpdf, Adobe Acrobat online, PDF24 Tools, Sejda, CloudConvert ($9.99/mo) and Foxit Editor ($9.99/mo), which all transfer your files to AWS, Azure or their own datacenters (even with TLS 1.3 in transit, the file still lands on a server they control). Because no data leaves your device, the legal definition of a data transfer under GDPR Art. 4(2) and a use under HIPAA 45 CFR §164.502 does not apply — useful when merging signed contracts, medical records, tax returns, attorney-client work product or anything covered by an NDA, IRS Pub 1075, FRCP Rule 34 ESI duties or the SEC Reg S-P safeguarding rule.

Yes — by design. Because PDFs never leave your device, no personal data is processed by iFillPDF, so the legal definition of a data transfer under GDPR Art. 4(2) does not even apply. For HIPAA, the same client-side flow keeps iFillPDF outside the Business Associate role under 45 CFR §160.103 because PHI is not created, received, maintained or transmitted on our infrastructure. For optional account storage, encrypted backups live on Hetzner Falkenstein eu-central under the EU TADPF perimeter, outside US Cloud Act 50 USC §3024 and FISA 702 reach.

No cap on the number of files; each individual PDF must be 100 MB or smaller, and beyond that your browser RAM is the real ceiling since everything runs in the tab. For long stacks expect a few extra seconds while your CPU does the work — typically 1-3 seconds per 100 pages on a 2020+ laptop. Compare to Sejda which caps free users at 50 MB total and 200 pages, Smallpdf which caps at 2 files/day on free, and PDFescape ($5.99/mo) which caps at 100 pages.

Partly — here is the honest split. Preserved: everything that lives on the page itself, meaning content streams, embedded fonts, images, page rotation, AcroForm field widgets and the in-page tag structure. Not preserved: bookmarks (PDF outlines), named destinations, document-level JavaScript and document-level XMP metadata, because the merge builds a fresh document and copies pages into it. Any digital signature is also invalidated, since it covered the original file. Smallpdf, CloudConvert and Combine PDF.com drop outlines on their free tiers too; Adobe Acrobat Pro is the tool that genuinely keeps them, at $19.99/month.

Yes — any modern browser (Chrome 90+, Safari 15+, Firefox 100+, Edge 90+, Brave, Arc, Opera) on any OS. Nothing to install. Works on iPad, on Chromebook in school networks where installs are blocked, and on Linux where Adobe Acrobat Pro is unavailable.

Yes. Output is a plain standards-conformant PDF — accepted by IRS e-file, USCIS Form filings, US federal courts via PACER/CM-ECF (FRCP Rule 5(d)(3)), state courts via Tyler Odyssey eFile, ACH/wire bank document portals, and HRIS systems like Workday, BambooHR and ADP. There is no PDF/A export mode: if a filing rule names ISO 19005 PDF/A explicitly, convert after merging with a dedicated tool. And note that merging invalidates any pre-existing digital signature on the source files — merge first, sign last.

Three reasons. Cost: Adobe Acrobat Pro is $19.99/month ($240/year), Smallpdf $9/month ($108/year), iLovePDF Premium $7/month ($84/year), Sejda $7.50/month, Foxit $9.99/month, UPDF $9.99/month, Soda PDF $7.99/month — iFillPDF is free forever. Privacy: all of them upload your PDF to their servers (Adobe to AWS US-East, Smallpdf to AWS Frankfurt, iLovePDF to Hetzner but with retention logs, PDF24 to a Geek Software GmbH datacenter in Germany) — iFillPDF processes locally in your browser, no upload. Friction: Smallpdf forces signup after 2 files/day, Sejda caps at 50 MB, Adobe requires an Adobe ID — iFillPDF requires zero signup.